1. Technical Field
The present invention relates to a level shifter and a display device having the level shifter, and more particularly, to a level shifter having a single input terminal and a display device having the level shifter.
2. Discussion of the Related Art
A liquid crystal display (LCD) has become one of the most widely used flat panel displays since its small size, thinness, and low power consumption make it suitable for use in many electronic devices. For example, the LCD is commonly found in a variety of electronic devices such as flat screen televisions, laptop computers, cell phones, and digital cameras.
There are two main types of LCDs currently used in electronic devices; they are passive matrix and active matrix. Since an active matrix type LCD uses thin film transistors as switching elements for displaying a moving image, they are much brighter and sharper than passive matrix displays of the same size and generally have quicker response times. Thus, active matrix displays are increasingly becoming the choice of laptop computer and flat screen television manufacturers.
The active matrix type LCD typically includes a plurality of gate lines, a plurality of data lines and a plurality of pixels that are defined by the gate and data lines to display an image. Each of the pixels includes a liquid crystal cell that varies a light transmittance in response to a voltage level of a data signal that is applied to the pixels through the data lines. Each of the thin film transistors is located on a portion of one of the pixels where one of the gate lines crosses one of the data lines. The thin film transistors are used to control an input of the data signal that is applied to the liquid crystal cells based on a scan signal that is applied to the pixels through the gate lines.
The active matrix type LCD also includes a level shifter that is used to elevate a level of one of a plurality of externally provided signals input from an integrated circuit to drive an LCD panel. For example, the level shifter may increase the level of one of the signals from about 3.3V to about 5V. A conventional level shifter typically includes dual input terminals for receiving such externally provided signals; however, when the level shifter includes the dual input terminals, the number of input pads and a size of the level shifter increases, thus increasing the power consumed by the LCD panel.